I thought it might be hormonal, like the heartburn ("Progesterone relaxes the esophageal sphincter during pregnancy, which makes you more susceptible to heartburn") and palpitations ("Resting heart rate increases during pregnancy and sometimes leads to minor heart rhythm irregularities, which can sometimes feel like your heart is galloping through your chest").
Today, fatigue has hit. I keep falling asleep on the sofa. Great timing, as tomorrow is the day my school breaks up for the summer and I'll be 11+6 the day we go back!